Backyard Aquaponics
A place to discuss aquaponics

I planted a couple bathtubs with various seed 2 weeks ago. Beetroot came up but was promptly burnt off by the heat in the gravel. Only thing that has survived is a pak choy that is being shaded by a big zuch leaf.
Have planted a couple hundred mixed seeds in net pots I got from Rupe, see what happens there. The seed is a couple seasons old, so may not be particularly viable, will see.

I planted some cucumber, zucchini and capsicum seeds about a month ago and they have come up successfully so planted some lettuce and snow peas last week and they are starting to come up well. Will need to thin out the lettuces eventually.

Do you actually sow the seeds right in the gravel, or do you put them on something to keep them from floating away? I worry that they will float away during the flood cycle. I thought of putting them into a narrow fold of tissue paper or something biodegradable like that, just to keep them in place until they sprout. Maybe I am over analyzing this, but what's a newbie to do.....

Beltie, I throw mine on the gravel and roll the rocks around a bit to get them to drop down below the surface.
Maybe do some tests with cheap small seeds, like bulk alfalfa or dill (sold for eating not growing, so very cheap in comparison).
Sprout some in cotton wool or paper towel soaked in water, and compare the success rate of sprouted seeds to how many come up thrown straight in the gravel.

The flood cycle should not fill above the top of the media, and in most cases, not within 20 - 40 mm of it.
The possibility of the seeds being swept away in the flood/drain cycles does not seem to be a problem for larger seeds (as small as onion seed or tomato, as most people who use this method do not seem to be having problems.
I have started only a few months ago and have planted some seeds by direct sowing into the gravel and others in a sand bed at the flood max level to ensure that it remains moist for the seeds.

With smaller seeds like leyyuce, I prefer to use the sand bed to raise seedlings.

Regards,
Tony

I suppose the issues with flood cycle sweeping seeds away or small seeds falling too deep will be a function on the size of your gravel.

I'm using 1/2" brown river rock. Perhaps a bit big or coarse compared to what some are using but I germinated some broccoli seed directly in it without needing bits of tissue or paper towel to hold the seed in place. However, a bit of cotton ball, tissue, paper towel, etc will work to hold and keep moist smaller seeds that are more likely to wash away like lettuce or carrots. The bits of stuff can also make it easier to spot where you put seeds so you know what is coming up and what failed to germinate.

Janet,
Have you tried chamomile tea for your seedlings? I hear it is good for fighting damping off of indoor started seedlings. I believe the method is to brew some weak herbal chamomile tea, allow to cool, and apply to the seedling bed/seedlings with a hand spray bottle. I've not tried it myself but for a while I was having real trouble with some seeds that I'd start indoors and then transplant out into potting mix outdoors.

nothing i planted directly into the gravel did any good because of the heat from the gravel burning the new leaves.
if your growbed doesn't have shade don't plant in summer.
there's no issue with planting seedlings if you give the root ball a quick rinse, i found soaking in a tub of water for 10 min and swirling the plant in the water got plenty off.

Apparently bathing the root ball in seasol (or equivalent seaweed tonic) will help transplant success.

You may try planting the seeds in a washed cocopeat in small tubes
buried in the GB and when big enough, tip out of the tube and replant back.

Just a note - I have digging things up from my garden and transplanting them - works well if they are small. I have direct seeding lettuce, radishes, beets, leeks - all did well. We also raised tomatoes in the nursery and transplated them - they are doing great too.

In other words, all is doing well - but we have perfect temperatures, and of course trained nursery people.

Things I have seeded directly in my 3/8" gravel

Beets
Cantaloupe
Carrots
Celery
Corn
Cucumbers,
Peas, Sweat Climbing
Peppers, Bell and banana
Radishes
Spinach
Squash, yellow summer
Sunflower
Tomatoes
Watermelon

I have had better success with direct seeding than seedling transplants. I think some of the reasons my transplants fail is because I am unwilling to properly harden off the new sprouts.. I have never lost a plant that I transplanted from the store to the gravel. I just prefer to not use the store bought plants because they very often come with pest that hatch out and devour the plants.

Smaller seed like celery I always over do the seeding because some do get to deep in the gravel to come up. I just thin back to the plants I want after a couple weeks.